Air dryer assembly with manifold system

ABSTRACT

An air dryer assembly with manifold system provides increased drying capacity for pressurized air systems, such as vehicle braking systems. A manifold connected to the supply ports of two adjacent air dryers allows parallel flow of air through the separate air dryers. An identical manifold connects to the delivery ports of the two air dryers to combine the clean, dry air from the delivery ports. Similar manifolds connect the control and purge ports of the dryers to allow simultaneous regeneration of the desiccant canisters. An assembly combining two air dryers, two pretreatment units, and manifolds connecting the supply, delivery, control, and purge ports of two air dryers is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to air dryers, and morespecifically to a manifold system for connecting two or more air dryersinto a single assembly.

2. Description of Related Art

Pneumatic braking systems are widely used in heavy-duty vehicles such asbuses, trucks, and trailers. Such a system typically includes, at aminimum, an air compressor for producing pressurized air, a reservoirfor storing pressurized air, and an air dryer for removing moisture andother contaminants from the air flowing through the system.

The air dryer is an essential element of the system as it removesmoisture and contaminants that would otherwise degrade the operation ofthe various components of the braking system. One common type ofconventional air dryer includes a dryer body having a removabledesiccant cartridge and supply, delivery, and control ports. In normaloperation, pressurized system air is directed to the supply port on thedryer body where passageways and an inner chamber formed in the bodyroute the supply air to the desiccant cartridge. The desiccant cartridgetraps moisture and other contaminants in solid, liquid and vapor form.From the desiccant cartridge, the clean, dry air flows through the dryerbody to the delivery port and on to the remainder of the pressurized airsystem.

Typical air dryers also operate in a regeneration or purge mode whereair is routed in a reverse direction through the desiccant cartridge toexpel trapped contaminants and moisture from the cartridge. Applyingpressurized air to the control port of the dryer body actuates a purgevalve in the dryer body so that air from the system reservoir isdirected in a reverse direction through the desiccant cartridge. Thereverse flowing air is typically vented through a purge port to theatmosphere along with the previously trapped moisture and contaminantsfrom the desiccant cartridge.

While single air dryers are useful and serve their intended purpose,changes in the industry and changes in maintenance expectations havedriven the need for additional air drying capacity. Larger vehicles, forexample, typically require correspondingly larger air systems and airdryers. A desire for longer maintenance intervals of the air dryer(i.e., changing the desiccant cartridge less often) likewise requires adryer having increased capacity.

Various ways of providing increased air drying capacity have beenproposed. For example, one approach has been to simply plumb two or moresingle air dryers into a pressurized air system using a combination ofmultiple hoses and fittings. This approach has numerous drawbacks,including the relatively large amount of space required to accommodatethe arrangement of external hoses and fittings and the overallcomplexity of the arrangement. Other drawbacks include increasedreliability problems introduced by the numerous additional hoses,fittings, and joints, as well as the increased cost associated with theexternal plumbing and fittings.

Another approach to increasing drying capacity has been to physicallyincrease the size of the air dryer body and/or desiccant cartridge. Thisapproach requires not only the design and manufacture of new parts(e.g., a larger size body and larger size desiccant cartridge), but alsoincreased inventory costs as the new parts must be maintained ininventory along with the existing parts. Furthermore, an increase insize of a desiccant cartridge does not necessarily proportionallyincrease the drying capacity of the cartridge. Thus a desiccantcartridge that is twice the size does not necessarily double the dryingcapacity or double the corresponding maintenance interval.

Yet another approach is to provide a unibody air dryer hosting twodesiccant cartridges. This approach likewise requires a separate airdryer body part which must be manufactured and maintained in inventory,incurring the detrimental effects as discussed above.

Thus, it can be seen that there remains a need in the art for an airdryer having increased drying capacity.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to an air dryer assembly havingincreased drying capacity incorporating a manifold system for use withtwo or more air dryers. In one aspect, the manifold system of thepresent invention comprises a supply manifold having an interiorpassageway fluidly connecting two flow apertures. The flow apertures areconnected to the supply ports of two air dryer units with the air dryerunits positioned side-by-side. The manifold is secured to the dryers ina manner to provide a fluid flow path from the manifold to the supplyports. A manifold port, preferably positioned along the supply manifoldmidway between the two flow apertures, allows supply air to be directedinto the manifold, through the interior passageway to the supply portsof the two air dryers.

In another aspect of the present invention, the manifold systemcomprises a delivery manifold having an interior passageway fluidlyconnecting two flow apertures. The delivery manifold is secured to thedryers in a manner to permit fluid flow through the delivery ports ofadjacent air dryer units to the flow apertures of the manifold. Air fromthe delivery ports of the two air dryer units is directed through thepassageway to a manifold port that is preferably positioned midway alongthe delivery manifold.

In yet another aspect of the present invention the supply manifold anddelivery manifold are identical. In yet another aspect, the manifoldsare low-profile having a minimal depth from front to back such that themanifolds extend outwardly from the air dryer bodies less thanapproximately one-fifth of the depth of the air dryer bodies.

In another aspect of the present invention, the supply manifold anddelivery manifold have an elongated U-shape configuration that alignsthe two flow apertures at the ends of each of the manifolds in adifferent plane than remainder of the manifold. In this embodiment, oneof the supply or delivery manifolds is secured to the dryer bodies withthe ends of the manifold extending downwardly and the other manifold issecured to the dryer bodies with the ends of the manifold extendingupwardly such that the flow apertures of the supply and delivermanifolds and associated supply and delivery ports are aligned. Thisparticular configuration allows both manifolds to be compactly securedadjacent the dryer bodies without a portion of either manifold blockingconnection of the other manifold and without any portion of a manifoldextending around, under or above any other portion of a manifold.

In another aspect of the present invention, the manifold systemcomprises a control manifold comprising an interior passagewayconnecting two flow apertures. The control manifold is connected toadjacent air dryers in a manner to permit fluid flow through the flowapertures to the control ports of the adjacent air dryers. A manifoldport, preferably positioned approximately midway between the flow ports,allows air to be directed into the manifold and to both control ports.

In another aspect of the present invention, the manifold systemcomprises a purge manifold comprising an interior passageway connectingtwo flow apertures. The purge manifold is connected to adjacent airdryers in a manner to permit fluid flow from the purge ports of adjacentair dryers to the flow apertures. A manifold port, preferably positionedapproximately midway between the flow apertures, allows air to bedirected from each of the purge ports, through the manifold and out themanifold port.

In yet another aspect of the present invention, an air dryer assemblycomprises first and second air dryers positioned adjacent one another,each comprising an air dryer body and desiccant canister, wherein bothair dryers are connected to a common mounting bracket. Two pretreatmentunits operable to remove oil, water, and large contaminants from the airstream are connected to the same mounting bracket. Manifolds asheretofore described are connected to the air dryers in a manner topermit fluid flow from the manifolds to the respective supply ports,delivery ports, control ports, and purge ports of the adjacent airdryers. A pretreatment manifold connects the output ports of the twopretreatment units, with a hose directing the airstream from thepretreatment manifold to the supply manifold port.

In another aspect of the present invention, any one or all of themanifolds are connected to the adjacent air dryers via connectors havingfluid flow passageways formed in the connectors, such as banjo bolts.The connectors secure the manifold to the adjacent air dryers byextending through the flow apertures of the manifold into the respectiveports of the air dryers.

Additional aspects of the invention, together with the advantages andnovel features appurtenant thereto, will be set forth in part in thedescription which follows, and in part will become apparent to thoseskilled in the art upon examination of the following, or may be learnedfrom the practice of the invention. The objects and advantages of theinvention may be realized and attained by means of the instrumentalitiesand combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an air dryer assembly employing amanifold system in accordance with an exemplary embodiment of thepresent invention.

FIG. 2 is a front view of the air dryer assembly of FIG. 1.

FIG. 3 is a top plan view the air dryer assembly of FIG. 1.

FIG. 4 is a rear view of the air dryer assembly of FIG. 1.

FIG. 5 is a perspective view of an exemplary single air dryer unit ofthe air dryer assembly of FIG. 1.

FIG. 6 is a cross-sectional view of the single air dryer unit of FIG. 5attached in the air dryer assembly of FIG. 1.

FIG. 7 is a perspective view of a manifold in accordance with anexemplary embodiment of the present invention.

FIG. 8 is an end view of the manifold of FIG. 7.

FIG. 9 is a sectional view of the manifold of FIG. 7 showing a uniforminternal passageway.

FIG. 10 is perspective view of a banjo bolt used in an exemplaryembodiment of the manifold system of the present invention.

FIG. 11 is a side cut-away view of the banjo bolt of FIG. 10.

FIG. 12 is an exploded view of an air dryer depicting the supply portsand delivery ports of two single air dryer units connected with amanifold system in accordance with an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

An air dryer assembly employing a manifold system in accordance with anexemplary embodiment of the present invention is shown generally inFIGS. 1-4 as numeral 10. Air dryer assembly 10 includes first and secondsingle air dryers 12, 14 positioned adjacent to each other in aside-by-side configuration. Each single air dryer 12, 14 comprises anair dryer body 16, 18, and a desiccant canister 20, 22. As will beexplained in more detail below, each dryer body further comprisessupply, delivery, and control ports, with internal passageways and aninner chamber for directing the flow of air through the dryer body.

Both single air dryers 12, 14 are attached to a common mounting bracket24 such that the entire air dryer assembly can be mounted to a bulkheador other surface in the vehicle. Supply and delivery manifolds 26, 28,each comprising an internal passageway fluidly connecting a center portto flow apertures at opposite ends of the manifold, connect the supplyports 30, 32 and delivery ports 34, 36 of the adjacent single airdryers, respectively. Banjo bolts 38, 40, 42, 44 fluidly connect theairflow apertures at the ends of each manifold 26, 28 to its associatedsupply or delivery port.

Two pre-treatment units 46, 48 are mounted at one end of the assembly,near second air dryer 14, via bracket 50. Each pretreatment unit isconfigured to connect to a corresponding input air line 52, 54, with theoutput of each pretreatment unit connected to a pretreatment outputmanifold 56. Pretreatment output manifold 56 combines the output fromboth pretreatment units, with hose 58 directing that output to thecenter port of supply manifold 26, which is connected to the supplyports of the two single air dryers as described above.

Pretreatment units 46, 48 are preferably condenser/separator unitsoperable to remove oil, liquid, and other large contaminants from theair stream before the stream is introduced into the air dryer. Byremoving such contaminants upstream, the life of the desiccant in theair dryer is significantly increased. Air enters the pretreatment unitthrough an inlet port at the side of the unit and expands therebycooling the air. The cooling of the air causes oil, water, and othercontaminants to condense and separate from the air, running to thebottom of the pretreatment unit. The clean air exits the pretreatmentunit through an outlet port on the top of the unit. An automatic drainvalve at the bottom of the unit operates with each application of thebrakes to expel the separated oil, water, and contaminants.

Purge manifold 60 is connected to the purge ports of adjacent single airdryers 12, 14, via banjo bolts 62, 64. A control manifold 66 issimilarly connected to the control ports of adjacent single air dryers12, 14 using banjo bolts 68, 70.

As seen in FIG. 4, three bolts 72 a, b, c and 72 d, e, f attach each ofthe air dryer bodies to assembly mounting bracket 24, with each boltextending through apertures in the bracket and into correspondingthreaded mounting holes in the air dryer body. Pretreatment mountingbracket 50 likewise attached to assembly mounting bracket 24. With theair dryers and pretreatment units attached to assembly mounting bracket24, the entire air dryer assembly can be mounted to fasteners positionedin a bulkhead or other surface using keyhole slots 74, 76 formed inassembly mounting bracket 24. Thus, the entire air dryer assembly can bepre-assembled, with the air dryer bodies, desiccant cartridges,manifolds, and hose attached as described above, and the entire assemblyattached into a vehicle as a single unit. Similarly, the entire assemblycan be removed from the vehicle for repair or maintenance, or the unitmay be left in place while various components are removed—for example,the desiccant canisters may be replaced without dismounting and removingthe entire assembly.

As also is apparent in FIG. 4, pretreatment mounting bracket 50 may beoriented in the opposite direction so that the pretreatment units arelocated at the opposite end of the assembly. Or, a second pretreatmentmounting bracket may be used so that a pretreatment unit is mounted ateach end of the assembly. These and other variations are within thescope of the present invention.

With the configuration of the air dryer assembly generally set forth,each component and the operation of the assembly will now be describedin more detail.

Looking to FIG. 5, a representative, exemplary single air dryer 12comprises a dryer body 16 and desiccant canister 20. Dryer body 16includes a supply port 30 to receive pressurized air to be dried, and adelivery port 34 to provide dried air for delivery to the brake system.Supply and delivery ports 30, 34 are aligned adjacent one another alongthe front of dryer body 16. Each of the supply and delivery portsincludes a raised boss 33, 35 extending outwardly from the port, withthe inner surface 37, 39 of each port being threaded. The ports are thusconfigured to receive a complementary threaded fitting or fastener toattach and plumb the air dryer into a pressurized air system. As can beseen in the cut-away view of FIG. 6, a single air dryer of the assemblyof FIG. 1 comprises a series of internal passageways and an innerchamber for directing and controlling the flow of air through the dryerbody. A typical air flow through the air dryer is for air to be receivedinto the supply port 30, directed through a passageway 78 to an innerchamber 80 of dryer body 16, and then into the desiccant canister 20where the air passes through various materials that remove moisture andother contaminants from the air. Air then flows from the desiccantcanister back into the air dryer body where it flows through furtherpassageways in the dryer body to the delivery port and out to theremainder of the system. In the single air dryer depicted, desiccantcanister 20 is a replaceable cartridge having at least one desiccantmaterial through which the air passes.

It should be understood that the single air dryer described is exemplaryand not limiting, and that the manifold system of the present inventionmay be equally used with air dryers having other configurations, dryingmaterials, etc.

Looking to FIG. 7, a close-up perspective view of supply manifold 26 isdepicted. Delivery manifold 28 is identical in structure to supplymanifold 26, but, as described hereafter, is oriented differently whensecured to the delivery ports. Supply manifold 26 comprises a generallyelongated, shallow “U”-shaped body 81 extending between first and secondflow apertures 82, 84 located at opposite ends of the manifold. The mainbody of supply manifold 26 is positioned along a first plane with theends of the manifold extending downwardly such that flow apertures 82,84 extend in a second plane. A cylindrical boss 86, 88 extends outwardlyaround each aperture on the front (outward) side of the manifold toprovide a mounting and sealing surface 90, 92 for the heads of banjobolts used to connect the manifold to the air dryer body. A longercylindrical boss 94, 96 extends rearwardly from the opposite side ofeach aperture to provide a stand-off and mounting surface for connectingthe manifold to the respective ports on the air dryer body.

As can be seen in FIGS. 8 and 9, an interior passageway 98 is formed inthe body of the manifold, extending the length of the manifold betweenthe two apertures, the passageway having a substantially uniform widthand depth along the entirety of its length. A threaded manifold aperture100 positioned approximately midway along the manifold body provides afluid connection to interior passageway 98. A raised boss 102 extendsoutwardly around threaded manifold aperture 100 to provide a surface forconnecting a hose or fitting to the port, with complementary threadingon hose or fitting engaging with the threads in the aperture port tosecure the connection to the manifold. Manifold 26 is preferably formedfrom a strong, lightweight material such as cast aluminum. Manifold 26is preferably formed as a “low-profile” manifold having a minimal depthfrom front to back such that the depth of the installed manifoldcomprises less than approximately one-fifth of the depth of the airdryer bodies.

Looking to FIGS. 10 and 11, an exemplary banjo bolt 104 used to connectthe manifold to the air dryer is depicted. Banjo bolt 104 comprises agenerally cylindrical body portion 106 extending between first andsecond ends, with threads 108 formed along the lower half of the body,and a hex head 110 capping the upper half of the body for attaching andremoving the bolt using standard tools. Cylindrical body 106 is hollow,forming a primary passageway 112 extending the length of the body of thebolt. Perpendicular passageways 114, 116 are formed through the bodynear the head of the bolt, the passageways are spaced equally around theperimeter of the upper portion of the body of the bolt. The crosspassageways intersect the primary passageway so that a fluid connectionexists between each of the holes and the primary passageway such thatair can flow between any or all of those holes and the primarypassageway. Banjo bolt 104 is preferably formed from a strong materialsuch as steel.

Looking to the manifold of FIGS. 7-9 in conjunction with the banjo boltsof FIGS. 10 and 11, it can be seen that with banjo bolt 104 insertedinto a flow aperture 82, 84 of the manifold 26, at least one of thepassageways in the body of the banjo bolt will be in fluid communicationwith at least a portion of the interior passageway 98 of the manifold.Thus, air flowing through the interior passageway of the manifold willflow into the passageways of the inserted banjo bolt and into theprimary passageway of the bolt. With the manifold connected to the portsof two adjacent single air dryers, air introduced into the manifold portwill be directed through the passageway to the banjo bolts at oppositeends of the manifold, and then through the banjo bolts into the port towhich the bolt is attached. With the manifold port being positionedapproximately midway between the ends of the manifold, fluid flowthrough the manifold port and into the supply and/or delivery ports willbe substantially the same resulting in parallel flow.

It should be understood that while a specific configuration of banjobolt is depicted in conjunction with the exemplary embodiment describedherein, other configurations of banjo bolts and of other connectors maylikewise be used to attach the manifolds to the air dryers. For example,the banjo bolts may simply include an inner passageway with a singlecross passageway or hole, or may include additional cross passageways tofluidly connect to the main passageway. In addition, simple bolts may beused, with a fluid flow between the manifold and the port occurringalong a gap between the diameter of the bolt body and/or around thethreads of the bolt. Or, a cap having a threaded portion to attach tothe port of the air dryer body and secure the manifold may be used.These and other connectors are contemplated by the present invention.

The airflow arrangement through the manifold, banjo bolts, and flowapertures is explained in more detail in conjunction with the air dryermanifold assembly depicted in FIG. 12. It should be noted that theassembly depicted in FIG. 12 shows an alternative placement of thesupply and delivery manifolds, i.e., in the opposite orientation asdepicted in the assembly of FIG. 2. Looking to FIG. 12, first and secondair dryers 112, 114 are positioned adjacent to each other, in aside-by-side configuration. Each air dryer comprises a dryer body 116,118 and desiccant canister 120, 122, as previously described. Each airdryer body includes a supply port 130, 132 for introducing air into thedryer, and a delivery port 134, 136, for delivering clean, dry air fromthe dryer, An elongated “U”-shaped supply manifold 126 as previouslydescribed is connected to supply ports 130, 132 so that the flowapertures 182, 184 at opposite ends of the manifold extend upwardly fromthe main body of manifold 126 to align with the respective supply ports130, 132 on each of the adjacent air dryers. A banjo bolt 138, 142extends through each of the flow apertures on the manifold and into thethreaded interior of the corresponding supply port 130, 132. With thebanjo bolts tightened into the supply ports, the manifold is held inposition onto the air dryers, with the head of the banjo bolt sealingagainst the surface of the boss surrounding each supply port. With thebanjo bolts thus attached, the interior passageway of the manifold is incommunication with the passageways of the banjo bolts such that airflows freely between the manifold and banjo bolts, into the supply portsand into the air dryer body. The manifold aperture 200 on the supplymanifold is thus in communication with both flow apertures/banjobolts/supply ports so that air introduced into the manifold through themanifold aperture 200 is directed to both single air dryers in which airis directed to the associated desiccant canister and dried as previouslydescribed. Because the manifold aperture 200 is positioned approximatelyat the midpoint of the manifold, and because the interior passageway ofthe manifold is of substantially uniform depth and width along thelength of the manifold, the volume of airflow into the each air dryer isapproximately equal, assuming that the air dryer bodies and canistersare essentially identical.

As also depicted in FIG. 12, delivery manifold 128 is similarlyconnected to delivery ports 134, 136 but in a reverse or mirroredorientation to that of the supply manifold 126. Delivery manifold 128 isconnected to delivery ports 134, 136 with flow apertures at oppositeends of the delivery manifold 128 extending downwardly from the mainbody of the manifold to align with delivery ports 134, 136. Deliverymanifold 128 is connected using banjo bolts 140, 144 such that themanifold port is in communication with the manifold passageway, banjobolts, and delivery ports to enable air from the delivery ports of eachair dryer to be communicated through the manifold, banjo bolts and flowapertures.

It should be noted that the identical U-shaped configuration of thesupply and delivery manifolds shown in the figures is particularly welladapted for use with air dryer units having supply and delivery ports inhorizontal alignment (i.e. where the ports are aligned in the sameplane). As shown in FIG. 12, all four ports (two supply, two delivery)fall into a single line or plane, with the supply ports on the two airdryers spaced apart the same distance as the delivery ports on the twoair dryers. The identical U-shaped supply and delivery manifolds can beoriented to permit connection of the manifolds to the ports without aportion of one of the manifolds blocking connection of the othermanifold, and without any portion of the manifolds extending over, underor around any other portion of the manifolds. In this manner, themanifolds can be compactly secured to the dryers without significantlyincreasing the overall depth (front to back) of the air dryer assembly.This exemplifies the adaptability of the present invention. While thisconfiguration of manifolds is preferable, the invention described hereinis not limited to that specific configuration, and other portarrangements and manifolds, including non-identical manifolds, may beused in accordance with the present invention.

With the configuration and operation of the individual components of theair dryer assembly set forth, the operation of an exemplary embodimentof the air dryer assembly of the present invention will be describedwith reference back to FIGS. 1-4.

Looking to FIGS. 1-4, two single air dryers 12, 14 are positionedadjacent to each other in a side-by-side configuration. Each single airdryer comprises an air dryer body 16, 18 and a desiccant canister 20,22. Each air dryer body includes a series of internal passageways andinner chambers for directing the flow of air within the dryer body andthrough the attached desiccant canister as previously described. The airdryers are attached to a mounting bracket 24 which allows the entireassembly to be attached to a bulkhead or other surface. A pair ofpretreatment units 46, 48 is attached to the mounting bracket at the endof the assembly, adjacent second air dryer 18. A purge manifold 56extends between and attaches to the corresponding outlet ports of eachpretreatment unit using banjo bolts.

Looking particularly to FIGS. 1 and 2, a supply manifold 26 extendsbetween, and is attached to, the corresponding supply ports on each ofthe air dryers using banjo bolts 38, 42. A hose 58, having fittings ateach end, connects between the manifold port of the pretreatmentmanifold 56 and the manifold port of the supply manifold 26.

A delivery manifold 28, identical to the supply manifold but oriented inthe opposite direction, extends between, and is attached to, thecorresponding delivery ports on each of the air dryers using banjo bolts40, 44. As previously explained with respect to the exemplary embodimentof FIG. 12, it should be understood that the orientation of the supplyand delivery manifolds may be reversed, still in accordance with thepresent invention.

A purge manifold 60 extends between, and is attached to, thecorresponding purge ports on each of the air dryers using banjo bolts,and a control manifold 66 extends between, and is attached to, thecorresponding control ports on each of the air dryer using banjo bolts.

With the assembly thus configured, the entire assembly (mountingbracket, air dryers, pretreatment units, manifolds, and hose) can beinstalled into a vehicle as an integral unit, the mounting bracket 24attaching to a bulkhead or surface in the vehicle using bolts or otherfasteners. Similarly, if necessary, the entire assembly can be removedfrom the vehicle as an integral unit. Of course, it should be apparentthat it is not required that the assembly be handled as an integralunit. For example, the desiccant canisters, manifolds, banjo bolts, andother components may be removed or replaced individually if desired.

Looking still to FIGS. 1 and 2, in operation, pressurized air is routedto the air dryer assembly via input lines 52, 54. Typically thepressurized air originates at an air compressor in the vehicle. Inputlines 52, 54 connect to the input port of the respective pretreatmentunit via a threaded fitting or connector. As described above, thepretreatment units remove oil, moisture, and large contaminants from theairstream, with the clean air exiting the pretreatment unit through anoutput port on the top of the unit. Pretreatment manifold 56 is attachedto the output ports of the pretreatment units with banjo bolts so thatthe output air from each pretreatment unit combines in the manifold andexits the manifold into hose 58.

Hose 58 delivers the combined stream of air to supply manifold 26, wherethe air is directed through the manifold, through the banjo bolts, andinto the supply ports x, x of each air dryer 12, 14. In each air dryer,as described above, the air is routed through internal passageways andan inner chamber, and through the desiccant canister. The desiccantcanister includes one or more desiccant materials operable to removemoisture and/or contaminants from the air stream. From the desiccantcanister, the clean, dry air is routed through the air dryer body andout through the delivery port. Delivery manifold 28, is attached to thedelivery ports of both air dryers via banjo bolts, the manifold combinesthe clean, dry air from both air dryers, the air exits the deliverymanifold through the threaded manifold port. In use in a vehicle brakingsystem, a fitting and air hose would be attached to the deliverymanifold port to direct the clean, dry air from the delivery manifold tothe remainder of the braking system.

Thus, in the exemplary air dryer assembly of the present invention, twosingle air dryers and two pretreatment units are arranged in closeproximity, attached to a common mounting bracket. Low profile manifoldsconnect to the supply ports and delivery ports of the two single airdryers using banjo bolts. The parallel flow configuration of the twosingle air dryers doubles the air drying capacity compared to using asingle air dryer unit, and correspondingly decreases the wear (andrequired maintenance) of each of the single air dryer units.

It should be understood that the assembly configuration depicted anddescribed is exemplary, other configurations and assemblies using themanifold and banjo bolts of the present invention are contemplated bythe present invention. For example, while the exemplary assemblyincludes two pretreatment units, those pretreatment units need notnecessarily be part of the assembly. An air dryer assembly comprisingtwo single air dryer units with manifolds connecting the supply anddelivery ports, with remote location of the pretreatment units is alsoanticipated by the present invention. Or, two single air dryer unitsconnected via supply and delivery manifolds may be used without anypretreatment units, with the incoming pressurized air routed directlyinto the supply manifold. Alternatively, a supply manifold may be usedto route incoming pressurized air to two single air dryer units, with nodelivery manifold—the air from each delivery port being routed toseparate areas or with separate hoses. These and other configurationsand variations are within the scope of the present invention. Inaddition, the manifolds may be configured to connect more than two dryerbodies together by adding additional flow apertures to be aligned withcorresponding ports on additional dryer bodies.

Looking still to FIGS. 1 and 2, with control manifold 66 connected tothe control ports on both air dryers with banjo bolts, a single inputthrough the manifold port x will operate the purge valve in each dryerto cause the dryer to operate in regeneration or purge mode as describedabove. With purge manifold 60 connected to the purge ports of the twosingle air dryers with banjo bolts, an external purge reservoir can beconnected to the purge manifold port so that pressurized air from thereservoir flows back across the desiccant to remove the moisture andcontaminants during the purge cycle. The moisture and contaminants areexpelled to the atmosphere via the air dryers' exhaust passage.

Thus, the air dryer assembly with manifold system of the presentinvention provides increased drying capacity for pressurized airsystems, such as vehicle braking systems. Low-profile manifoldsconnected to two adjacent air dryers allow parallel flow of air into thesupply ports of the air dryers, and combine the clean, dry air providedthrough the delivery ports. Similar manifolds connect the control andpurge ports of the dryers. Preferably, the supply and delivery manifoldsare identical, reducing the cost of separate parts and inventory. Theassembly of two air dryers mounted to a single mounting bracket with lowprofile manifolds connecting the supply and delivery ports provides acompact dryer assembly having increased drying capacity that occupies aminimal volume in a vehicles. With two pretreatment units included inthe assembly, the volume of the assembly is significantly reduced ascompared to separately mounted air dryers and pretreatment units, andeliminates the associated plumbing and fittings required in such aseparate setup.

The manifold system may be used to connect existing air dryers and/orpretreatment units together to increase the air drying capacity of avehicle without the need for manufacturing larger dryer bodies and/orpretreatment units. In addition, due to the modular nature of thesystem, the various components of the system (e.g. dryer bodies,desiccant canisters, manifolds and banjo bolts) can be mass produced andindividually replaced thereby saving on costs in both the manufactureand maintenance of the system. Thus, the use of existing air dryersfurther reduces the cost associated with implementing the increased airdrying capacity as compared to units requiring specialized air dryerbodies and/or specialized desiccant canisters.

From the foregoing it will be seen that this invention is one welladapted to attain all ends and objectives herein-above set forth,together with the other advantages which are obvious and which areinherent to the invention.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that allmatters herein set forth or shown in the accompanying drawings are to beinterpreted as illustrative, and not in a limiting sense.

While specific embodiments have been shown and discussed, variousmodifications may of course be made, and the invention is not limited tothe specific forms or arrangement of parts and steps described herein,except insofar as such limitations are included in the following claims.Further, it will be understood that certain features and subcombinationsare of utility and may be employed without reference to other featuresand subcombinations. This is contemplated by and is within the scope ofthe claims.

What is claimed and desired to be secured by Letters Patent is asfollows:
 1. A manifold system for interconnecting two or more air dryerunits, the manifold system comprising: a supply manifold comprising abody defining a supply passageway extending between first and secondsupply flow apertures and a supply manifold port defined in said bodybetween said supply flow apertures and in fluid communication with saidsupply passageway, wherein said first and second supply flow aperturesare configured to align with first and second supply ports of two airdryer units positioned in side-by-side relationship; and at least oneconnector configured to secure said supply manifold to each of said airdryer units in a manner to provide a fluid flow path from said supplypassageway to said supply ports when said supply manifold is secured tothe air dryer units.
 2. The manifold system of claim 1, wherein said atleast one connector comprises first and second connectors having a fluidflow path formed therein, wherein said first and second connectors areconfigured to extend through said first and second supply flowapertures, respectively, and to engage with said first and second supplyports to attach said manifold to said two air dryers.
 3. The manifoldsystem of claim 1, wherein said supply manifold comprises an elongatedhollow U-shaped body defining said supply passageway.
 4. The manifoldsystem of claim 1, further comprising a delivery manifold comprising abody defining a delivery passageway extending between first and seconddelivery flow apertures and a delivery manifold port defined in saidbody between said delivery flow apertures and in fluid communicationwith said delivery passageway, wherein said first and second deliveryflow apertures are configured to align with first and second deliveryports of said two air dryer units positioned in side-by-siderelationship; and at least one delivery connector configured to securesaid delivery manifold to each of said air dryer units in a manner toprovide a fluid flow path between said delivery passageway and saiddelivery ports when said manifold is secured to said air dryers.
 5. Themanifold system of claim 4, wherein said supply manifold and saiddelivery manifold are identical.
 6. The manifold system of claim 4,wherein said at least one delivery connector comprises third and fourthconnectors having fluid flow paths formed therein, wherein said thirdand fourth connectors are configured to extend through said first andsecond delivery flow apertures, respectively, and to engage with saidfirst and second delivery ports to attach said manifold to said two airdryers.
 7. A manifold system for interconnecting two air dryer units,each air dryer unit including supply, delivery, control, and purgeports, said manifold system comprising: a supply manifold having apassageway extending between first and second supply apertures; adelivery manifold having a passageway extending between first and seconddelivery apertures; a control manifold having a passageway extendingbetween first and second control apertures; and a purge manifold havinga passageway extending between first and second purge apertures, whereinsaid supply, delivery, control, and purge manifolds are connected tosupply, delivery, control, and purge ports, respectively, of first andsecond air dryer units.
 8. The manifold system of claim 7, wherein saidsupply manifold and said delivery manifold are identical.
 9. Themanifold system of claim 7, further comprising a plurality of connectorshaving an air passageway defined therein, wherein each of said supply,delivery, control, and purge aperture is attached to its respectivesupply, delivery, control and purge port with a connector such that saidmanifolds and said ports are in fluid communication through saidconnector.
 10. The manifold system of claim 7, wherein said supplymanifold body comprises a low-profile cross sectional depth, such thatsaid attached supply manifold extends from said air dryer units lessthan approximately one-fifth of a depth of one of said air dryer units.11. The manifold system of claim 9, wherein at least one of saidconnectors is a banjo bolt.
 12. An air dryer assembly, comprising: firstand second air dryer units, each of said air dryer units comprising adryer body, a desiccant canister, a supply port and a delivery port; asupply manifold attached between said supply ports of said air dryerssuch that said supply ports are in fluid communication; a deliverymanifold attached between said delivery ports of said air dryers suchthat said delivery ports are in fluid communication; whereby pressurizedair applied to said supply manifold is directed to each of said airdryer supply ports, through each of said air dryer bodies and desiccantcanisters, and to said delivery manifold.
 13. The air dryer assembly ofclaim 12, further comprising first and second pretreatment units influid communication with said supply manifold.
 14. The air dryerassembly of claim 12, wherein said supply manifold and said deliverymanifold are identical.
 15. The air dryer assembly of claim 12, furthercomprising a mounting bracket attached to each of said first and secondair dryer units and said first and second pretreatment units.
 16. An airdryer assembly, comprising: first and second air dryer units, eachcomprising an air dryer body in fluid communication with a desiccantcanister, said air dryer body comprising a supply port and a deliveryport in fluid communication with an inlet and an outlet, respectively,of said desiccant canister; a supply manifold connected between, and influid communication with, said supply ports of said first and second airdryer units; a pretreatment unit in fluid communication with said supplymanifold; and a mounting bracket, said bracket attached to each of saidfirst and second air dryer units and said pretreatment unit to affixeach of said elements in a fixed relationship.
 17. The air dryerassembly of claim 16, the air dryer assembly further comprising adelivery manifold connected between, and in fluid communication with,said delivery ports of said first and second air dryer units.
 18. Theair dryer assembly of claim 17, wherein said supply manifold and saiddelivery manifold are identical.
 19. The air dryer assembly of claim 17,wherein said supply manifold and said delivery manifold each comprise alow-profile cross sectional depth, such that said attached manifoldextends from said air dryer units less than approximately one-fifth of adepth of one of said air dryer units.
 20. The air dryer assembly ofclaim 17, further comprising a second pretreatment unit in fluidcommunication with said supply manifold.
 21. The air dryer assembly ofclaim 17, wherein said mounting bracket comprises a plurality of keyholemounting slots.